1. Field of the Invention
The present invention relates to a method for lining an inner circumferential surface of an existing pipe such as a sewer pipe with a lining material, and to a lining material collar for protecting one end part of the lining material.
2. Description of the Prior Art
In a conventional method of lining an existing pipe, as disclosed in Japanese Patent Publication No. 1980-43890, a lining material comprising a tubular (bag shaped) flexible resin absorber impregnated with a liquid setting resin is inserted into the existing pipe with the liquid setting resin in an uncured form. The lining material is then brought into pressure contact with an inner circumferential surface of the existing pipe by air pressure, water pressure, and the like, and cured by heating and hardening the setting material so that it becomes tubular with a shape the same as the inner circumferential surface of the existing pipe.
In such a lining method, if, for example, a branch pipe that intersects the main pipe and whose diameter is comparatively small is lined from a pipe opening of the branch pipe opened at a portion that intersects the main pipe, then a lining material is used that is provided with a flange at one end part, and that flange is bonded and fixed to the inner circumferential surface of the main pipe (hereinafter, referred to as the flange fixing surface) surrounding the pipe opening of the branch pipe. This is to position and fix one end part of the lining material to the pipe opening, and to prevent the infiltration of external ground water, rainwater, and the like, by sealing a gap between the inner circumference of the branch pipe and the outer circumference of the lining material at the circumferential edge part of the pipe opening of the branch pipe.
The flange comprises a resin absorber impregnated with a liquid setting resin; however, unlike the branch pipe lining material, the flange is manufactured as a hardened object by curing the impregnated liquid setting resin in advance at the factory, and carried into the construction site for use in a state integrally joined with one end part of the lining material.
To make the abovementioned seal perfect by tightly sealing the entire surface of the flange to the flange fixing surface, it is necessary to make the shape of the flange curved corresponding to the flange fixing surface, and to match the angle of the flange surface relative to the axial direction of the branch pipe liner to the angle of intersection of the main pipe with the branch pipe. Consequently, the angle of intersection of the main pipe with the branch pipe, and the shape (curvature, and the like) of the flange fixing surface are measured beforehand by performing a pre-examination of the lining construction. According to the dimensions thus measured, the flange is manufactured as a hardened object whose shape is matched to the measured shape, and the flange is joined to one end part of the lining material so that it forms the measured angle of intersection.
If, after lining the branch pipe, the main pipe is lined including the portion that intersects with the branch pipe, then the lining material of the main pipe unfortunately plugs up the pipe opening of the branch pipe at the intersecting portion. This requires the forming of a hole by a drill and the like in the lining material of the main pipe at the portion opposing the pipe opening of the branch pipe. In this case, a short, tubular collar provided with a flange of a metal such as stainless steel is used to protect the flange and the end part of the branch pipe liner from being cut by the drill. The tubular part of the collar is mated with one end part of a branch pipe lining material beforehand, and the collar is fixed by tightly sealing and bonding its flange to the lower surface of the flange of the lining material. Even with the manufacture of this collar, the angle of the tubular part of the collar with its flange is matched to the angle of intersection of the main pipe with the branch pipe, measured by the previously discussed pre-examination.
Nevertheless, it may not necessarily be possible to accurately measure the angle of intersection of the main pipe with the branch pipe, and the shape of the flange fixing surface by the previously performed pre-examination. In particular, accurate measurement is problematic in cases where a person cannot enter the main pipe and perform a direct measurement because the diameter of the main pipe is small, and the measurement must be taken indirectly by a video camera vehicle, and the like.
The flange of the lining material is conventionally manufactured as a hardened object whose shape matches the shape of the measurement results, and joined to one end part of the lining material at an angle the same as the angle of intersection of the measurement results. If, therefore, the measurement error is large, then the flange of the lining material can no longer be tightly sealed and fixed to the entire surface of the flange fixing surface. In this case, the gap between the inner circumference of the branch pipe and the outer circumference of the branch pipe liner at the circumferential edge part of the pipe opening of the branch pipe can no longer be completely sealed by the flange, and the infiltration of external ground water, rainwater, and the like, can no longer be prevented.
In addition, the previously mentioned collar is fixed to one end part of the lining material according to the measurement results. If, therefore, the measurement error is large, then the flange of the lining material can no longer be tightly sealed to the entire surface of the flange fixing surface.
It is therefore an object of the invention to provide a method for lining an existing pipe that can completely seal a gap between the inner circumference of the existing pipe and the outer circumference of the lining material at a circumferential edge part of the pipe opening of the existing pipe, and a lining material protecting collar adapted for use in this method.